Bug 1635258 - Enable modern search configuration on beta. r=daleharvey

Differential Revision: https://phabricator.services.mozilla.com/D76863

browser/app/profile/firefox.js

@@ -404,7 +404,7 @@ pref("browser.search.widget.inNavBar", false);
 // The maximum amount of times the private default banner is shown.
 pref("browser.search.separatePrivateDefault.ui.banner.max", 0);
 
-#ifdef NIGHTLY_BUILD
+#ifdef EARLY_BETA_OR_EARLIER
   pref("browser.search.modernConfig", true);
 #endif